This application is based on Japanese Patent Application No. 9-366790 filed Dec. 26, 1997, the content of which is incorporated herein by reference.
The present invention relates to a control apparatus for an LSI, such as a communication LSI, incorporating a plurality of communication controllers for use in a computer system, etc., connected to a communication network, etc., and adapted to conduct communication, a method for controlling a communication LSI, and a distributed control network system having a communication LSI control apparatus.
With a recent advance of an LSI fabrication technique, it has been possible to incorporate a large-sized circuit or circuits into an LSI at low costs. Under this situation, more number of pins need to be used for a package, thus imparting a greater influence to the cost of the LSI than the circuit size. The use of more pins results in more costs. In the communication LSI for use in a conventional computer system, etc., on the other hand, a dedicated I/O pin is required for each communication controller.
If, therefore, a greater number of communication controllers are incorporated into the LSI, mote I/O pins are required for the LSI and more costs are involved, thus presenting a problem. Further, the communication LSI is used for a general-purpose application and usually incorporates a CPU, multi-channel ROM/RAM controllers, etc., therein. These I/O pins, if being not used in the system, will become useless.
It is better and effective to develop LSIs in accordance with the system used. In this case, however, a vast cost is involved in the development of the LSIs.
It is accordingly the object of the present invention to provide a control apparatus for an LSI, that is a communication LSI, having the function of allowing an I/O pin in the LSI to be switched in use to a communication port for specific communication controllers, suppressing the use of more I/O pins necessary to the LSI, enabling the mounting of an LSI package of less pins and ensuring a high general-purpose use at low costs, and a method for controlling a communication LSI and a distributed control network system having the communication LSI control apparatus.
In order to achieve the above-mentioned object of the present invention, a communication LSI control apparatus is provided which comprises communication control means for controlling communication in accordance with a plurality of different communication protocols, changeover information setting means for setting changeover information for selecting the communication control means, and selecting means for selecting the communication control means based on the changeover information set by the changeover information setting means and effecting a switching in a way to have the selected communication means correspond to a given I/O pin of the communication LSI.
According to the arrangement above, the communication control means corresponding to the different communication protocols is switched based on the set changeover information to correspond to a given I/O pin of the LSI. By doing so, it is possible to suppress the use of more I/O pins necessary to the LSI and, by doing so, to achieve a low-cost LSI package of less pins. Particularly, the present invention is useful for a communication LSI having communication control means adapted to at least one communication protocol for an information system network and a communication protocol for a control system network.
The present invention has the following arrangement so as to achieve the above-mentioned object.
The changeover information setting means is provided at an outside of the communication LSI and the setting of the changeover information is performed from the outside of the communication LSI.
When a computer system including the communication LSI is powered ON, the selecting means reads out the changeover information initially stored in the changeover information setting means and effects a switching of the communication control means based on the read-out changeover information.
Further, the selecting means switches the communication control means based on the control of a program for setting the changeover information initially set in the changeover information setting means.
When the computer system including the communication LSI is powered ON, the selecting means selects the communication control means based on a result of determination, by the communication control means, of a kind of communication network connected to the communication LSI.
Further, the present invention has the following arrangement in order to achieve the above-mentioned object.
A distributed control network system comprises a control client connected by a first communication protocol to a first communication network, a plurality of event-driven type distributed control microcomputers connected by a second communication protocol to a second communication network, and a local control server connected by the first communication protocol to the first communication network and adapted to control the distributed control microcomputer by the second communication protocol via the second communication protocol, the local control server having a communication LSI control apparatus, the communication LSI control apparatus comprising communication control means corresponding to the first and second communication protocols and adapted to control the communication, changeover information setting means for setting changeover information for switching the communication control means, and selecting means for selecting the communication control means based on the changeover information set by the changeover information setting means and for effecting a switching in a way to have the selected communication control means correspond to a given input/output pin of the communication LSI.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.